I bought my car nearly 5 years ago, the air conditioning worked like normal for the first year. Then the next summer I would just get hot air. I never really bothered with it until last week.

So I went to buy AC Pro refill refrigerant and also the gauge gun. Read all of the instructions and also watched a video or two. Initially hooking up the gauge gun it was in the Alert/Yellow zone i.e. about 55 PSI. So after some research I brought it down into the Filled/Green zone about 35 PSI now. However still no cold air.

When turning on my air con, the air con unit starts spinning (on the belt), 2 of the fans also start spinning however when touching the lines/pipes/aircon radiator doesn't really feel cold at all.

What should I be looking for as a next step?

  • Does the A/C unit start spinning, or is it just the outside portion (pulley)? When the A/C compressor is actually going, there's a electromagnetic clutch which engages and causes the actual pump to spin. Also, if you only have 35psi when the A/C is at rest, this means both the high side and low side are at 35psi. The low side which is what is typically measured by the "DIY" type of gauge. It should be ~35-45psi while it is running. High side while running is ~150-200psi (IIRC) when running. Commented Jun 17, 2023 at 18:06
  • @Pᴀᴜʟsᴛᴇʀ2 The AC unit outer spindle can see few bolt heads or what it's called starts spinning, with AC off its stationary. Yeah I only have access to the high side. The PSI doesn't change I believe whether AC is on/off I will double check and monitor to confirm.
    – Dave1UK
    Commented Jun 17, 2023 at 18:48
  • If you are using an "AC Pro", that is the low side. You should input your refrigerant into the low side. If you tried to do that with the AC running, it would push refrigerant back into your can. Commented Jun 17, 2023 at 19:30


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